核心问题
He described it as ‘a very agreeable situation located within two small hills in the midst of which flowed a great river.’ (New Concept English, Book 3, L.17)
为什么定语从句 in the midst of which flowed a great river 中的主语和谓语要倒装？
词典解答
作者把从句的主语 a great river 放在句尾, 是为了使它处于信息焦点的位置, 使其传递新信息。见 end-focus 和 existential sentences in Chinese and English。